1. Field of the Invention
This invention relates generally to a method for manufacturing pet food. Specifically, this invention relates to a method of manufacturing pet food with an ultrasonic horn and an anvil and without the use of undesirable components such as plasticizers, dyes, chemicals or artificial preservatives.
2. Discussion of Related Art
Mirroring the obesity epidemic of their owners, pet obesity has become a real danger especially for those animals living in urban sedentary environments. Accordingly, pet owners are seeking to provide their pets a healthy and nutritious diet that is low in fat and low in calories. Additionally, according to current trends, many owners are seeking products which include high-quality, human grade ingredients, often organic, to provide their pets with all the natural elements that are necessary for a balanced diet, such as: protein, vitamins, minerals, fiber, antioxidants, amino acids, carbohydrates and omega 3 fatty acids. Further, owners desire ingredients which are ideally free of artificial preservatives and coloring. And, if such ingredients must be processed, the processing should be kept to a minimum to prevent the loss of the nutritional value.
Currently, there are three basic manufacturing processes widely used by the pet food industry, namely, extrusion, oven baked (biscuit process) and injection molding.
The extrusion process is primarily utilized for the production of dry pet food pellets, or kibble. During such process a mixture of raw materials is subjected to a rapid injection of steam, less than 3 minutes, and subsequently extruded under high pressure through a metal die. As the product reaches atmospheric pressure after leaving the extrusion die, the pellets expand in volume into crunchy, aerated products. The resultant kibble is allowed to dry, sprayed with oils, vitamins, fats and any other desirable ingredients that are heat-sensitive. This process has short-comings. First, the integrity and shelf life of extruded kibble is very vulnerable to inadequate packaging and storage conditions, since the fats and oils added after the extrusion on the product surface can easily become rancid if exposed to air for extended periods of time. For this reason, the process frequently involves the use of preservatives such as BHT and Ethoxyquin. Many pet owners seek to avoid these chemicals because they may cause disease and other medical concerns. Secondly, the product obtained by this process tends to be less digestible.
The oven baked or biscuit process entails a forming process, typically accomplished through forming rolls, in which a plastic dough mass is converted into individually shaped products which are subsequently oven baked in a slower, gentler heating action. The resulting products, regardless of their shape and size, are considered by pet owners more natural a more digestible. It is claimed that such slow process acts as a “pre-digest” of the kibble causing less strain on the animal digestive system and allows greater food absorption. Also, since fat, oils and vitamins are “baked in” rather than added on the product surface through spraying, they are less prone to deterioration and oxidation, consequently baked kibble enjoys a slightly longer shelf life when compared to their extruded relative. However, this process takes longer to produce than other current methods.
Lastly, Injection molding is the process of choice when complex full tri-dimensional shapes and significant hardness are attributes that are sought in the finished products. This process is similar to molding of thermoplastic parts, it requires a complex monumental type of equipment which must be contained in a properly conditioned ambient environment to prevent condensation from forming on the dies. Typically, for a multi-cavity die (6-8 cavities) the cycle time is around 1 minute and 45 seconds, so relatively slow. The product itself needs to be de-flashed and dried before packaging, while the resulting “spider” must be ground to be recycled. More importantly, the product formula allows for ingredients only in a fine particulate or powder forms, cannot contemplate any kind of significant inclusion. And, most critically, injection molding must include plasticizers, humectants, binders and fluidizers (cellulose, starches, glycerin, gelatin, propylene glycol, etc.) to facilitate the injection process. The resulting product, while visual pleasing in its tridimensional form, doesn't reveal the contribution of the individual raw materials (it's fully homogenized in color and texture) and it is seriously compromised in its nutritional profile due the additions of those ingredients functional only to the injection process.
Additionally, all three processes limit the addition of natural fibers. Therefore, it is unusual to find products made by any of these processes that have a fiber content greater than 6%.
In view of the above, a need exists for: A process that can use natural human-grade ingredients from the five groups of the food pyramid. A process of manufacture that is capable of delivering products whose nutritional profile is uncompromised by the addition of undesirable components, including fillers, plasticizers fluidizers, dyes, chemicals, artificial preservatives. A process that delivers a product where each ingredient is visible which contributes to the product's ultimate and unique appearance. A process that reduces or eliminates the use of ingredients which are known to produce allergic reactions in pets, including but not limited to wheat, glutens, brewer's yeast. A process that doesn't require the use of binders, including cellulose, gum, gelatin resulting in easily digestible products that will not swell, are highly soluble and will not cause intestinal occlusions in pets. A process which provides a product where the abrasiveness and natural roughness of the agglomerated ingredients results in a teeth cleaning action during the chewing process. A process that is highly versatile so as to produce items of complex shapes and textures beyond what is currently possible. A process that is highly flexible with respect to the nutritional profiles achievable, to include also dietetic ones delivering: High protein, Low Fat, High fiber (>15%) and Low overall calorie contents. A process that creates a product with a high fiber content which helps with the bowel movement and the cleansing of the intestinal tract. A process that eliminates the need for large assets such as ovens, cooker/extruders and injection molding machines as well the need for many peripheral systems.